Reaction products of boric acid and lithium hydroxide

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

All members of the category ‘Lithium salts of the oxyacids of boron (B)’ are formed in situ and are immediately formulated into grease thickeners which are marketed and used within the EU/EEA and exported. Extraction from the grease thickener products would need to be performed for testing to be conducted on the isolated substance itself. As testing requires a substantial quantity of material, it was decided to perform the testing on the only isolated, available product, dilithium tetraborate for this category approach.

All lithium borate substances are expected to be soluble in water and should exhibit essentially the same water solubility value since, in a water environment, all lithium borate salts will exist in equilibrium with boric acid.

Variations due to the range of trigonal and tetrahedral species between the substances are not expected to lead to any changes in the water solubility.

An experimental study on dilithium tetraborate provided a water solubility value of 141.2 g/L which indicates that the substance is very soluble in water. This result is consistent with the data reported in the CRC Handbook for lithium metaborate which states that the substance is very soluble in water. It is expected that the UVCB- Reaction products of boric acid and lithium hydroxide will also be equally as soluble. Read-across to the result for dilithium tetraborate is therefore proposed for the REACH registration of the UVCB-Reaction products of boric acid and lithium hydroxide.

Key result

Water solubility:

141.2 g/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

>= 9.35 - <= 9.44

Conclusions:

The UVCB-Reaction products of boric acid and lithium hydroxide is expected to be very soluble in water and have a solubility of around 141.2 g/L.

Executive summary:

All lithium borate substances are expected to be soluble in water and should exhibit essentially the same water solubility value since, in a water environment, all lithium borate salts will exist in equilibrium with boric acid. In an experimental study, dilithium tetraborate was found to have a water solubility value of 141.2 g/L which indicates that the substance is very soluble in water.

Read-across to the result for dilithium tetraborate is therefore proposed for this endpoint. A value of 141.2 g/L will also be reported for the UVCB-Reaction products of boric acid and lithium hydroxide since the any variations due to the range of trigonal and tetrahedral species between the substances are not expected to lead to any changes in the water solubility.  

Description of key information

All lithium borate substances are expected to be soluble in water and should exhibit essentially the same water solubility value since, in a water environment, all lithium borate salts will exist in equilibrium with boric acid.

 

An experimental study on dilithium tetraborate provided a water solubility value of 141.2 g/L which indicates that the substance is very soluble in water.  This result is consistent with the data reported in the CRC Handbook for lithium metaborate which states that the substance is very soluble in water.  It is expected that the UVCB-Reaction products of boric acid and lithium hydroxide will also be equally as soluble. Read-across to the result for dilithium tetraborate is therefore proposed for all lithium borate substances in this category.

Key value for chemical safety assessment

Water solubility:

141.2 g/L

at the temperature of:

20 °C